skirkland1980 Posted June 16, 2013 Share Posted June 16, 2013 Hello. I'm looking for suggestions for a cam grind for a L28ET in a full weight 280ZX turbo. I will be regrinding a stock camshaft so I'm limited on LSA. The car will be a 1/8 mile track dedicated race car for now. I need this car to accelerate a quickly as possible. I just installed a TH350 transmission w/4000 stall to help build boost on the line. It also has the stock R200 with stock ratio (3.45 or 3.54?)The car has a P90 head on it now but I'm considering an N42 that I have to boost static compression a little. I'd like to port and polish the head and have the complete head with cam to just swap out. I'm thinking about .500" lift and 272 advertised duration...? Any suggestions? Are there any tricks say with a split pattern cam? Maybe more duration on the exhaust?...less? Not sure...What about advancing or retarding the cam? Right now, with the stock cam the car is completely out of breath at 5500 rpm. I'd like to pull hard to around 6500rpm. The turbo is a TC4305. It should be up to the task. I'm also having some intake runners machined for a custom intake that I'm building. I'll start a separate thread on that later. Thanks. Quote Link to comment Share on other sites More sharing options...
Xnke Posted June 16, 2013 Share Posted June 16, 2013 (edited) Call Isky. There isn't a limit on LSA...but it may get impractical. I had a stock turbo cam re-ground to a 113LSA, no problem. You will need to go through and set up the lash pads properly, and getting the correct thickness may be spendy or take some work, but getting the cam cut isn't an issue. Elgin camshaft also has a few turbo grinds that work really well too. When you call for a custom camshaft, they will ask for head flow numbers, exhaust sizing, intake sizing, and desired output. Edited June 16, 2013 by Xnke Quote Link to comment Share on other sites More sharing options...
tooquick260 Posted June 16, 2013 Share Posted June 16, 2013 Isky is good, call and tell them what you have and what you want. They will steer you in a good direction. Just make sure your setup isnt going to change. I ended up changing tranny to a closer ratio box that I could have gone a little more aggressive on the profile of the cam. Quote Link to comment Share on other sites More sharing options...
Bernardd Posted June 16, 2013 Share Posted June 16, 2013 I ran that same turbo on my 83. My biggest issue was the torque converter with jatco auto. It was setup for 3k and I could have used a 3500 for better launches but it was still able to reach a 7.1 1/8th. I run an isky cam with a .470 lift cam with a 256 duration robello head. Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted June 16, 2013 Author Share Posted June 16, 2013 I ran that same turbo on my 83. My biggest issue was the torque converter with jatco auto. It was setup for 3k and I could have used a 3500 for better launches but it was still able to reach a 7.1 1/8th. I run an isky cam with a .470 lift cam with a 256 duration robello head. I would be ecstatic if I could run a 7.1. What type of intake were you running? That cam is a lot smaller than I thought it would need to run that time. Thanks Quote Link to comment Share on other sites More sharing options...
Bernardd Posted June 16, 2013 Share Posted June 16, 2013 Stock intake. What are your 60' times like? Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted June 16, 2013 Author Share Posted June 16, 2013 We race down pit road at Atlanta Motor Speedway and there is no timing system. If I had to guess 60' times I would say about 2.50. I really just need to be able to build boost on the line which I cannot. Here is a video of the problem I'm having. I am also using launch control, cutting sparks and timing. Quote Link to comment Share on other sites More sharing options...
Bernardd Posted June 16, 2013 Share Posted June 16, 2013 Where is the bang bang and flames? Are you doing the rich afr's with reduced timing on the 2 step? What rpms does your converter stall at? What rpms does the engine build boost at? Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted June 16, 2013 Author Share Posted June 16, 2013 The converter I just removed only stalled at 2000 rpm. Hopefully the one I just installed will get me to at least 3000. I think that's the reason my launch control isn't working as effectively. My turbo doesn't start pulling hard until 4500rpm. Quote Link to comment Share on other sites More sharing options...
roger280zx Posted June 17, 2013 Share Posted June 17, 2013 My turbo cam came from Elgin. It is a .505 .490 on a 112* lsa. I'm trying to reach 7k redline peaking around 6500. I'm no drag racer, but I will hit some of the GA tracks for WOT tuning. Maybe ill see you around. Quote Link to comment Share on other sites More sharing options...
Xnke Posted June 17, 2013 Share Posted June 17, 2013 Try running 3* of timing on the launch control and cutting 2 of 5 sparks; richen things up a *little* and see how it goes. Set the launch to hard limit you at 3500RPM, with the soft limit (the point when it starts retarding timing) at 2800. I bet that'll get you some boost on the line...works a treat on the ZXT here. Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted June 17, 2013 Author Share Posted June 17, 2013 I've played with the launch control quite a bit. I think the problem is the large turbine air ratio on my turbo. I'm hoping this new converter will help. I don't think it'll stall more than 3000rpm though... So about the cam, will the .500"/272 be a good choice or am I thinking too big? I want a winning car here. I'm planning on getting the Isky 7005-12 springs and 1624-st retainers. Roger280zx, have you done any porting to match your cam? How do you like it? Thanks Quote Link to comment Share on other sites More sharing options...
roger280zx Posted June 18, 2013 Share Posted June 18, 2013 The cam is in a box in my garage. The stainless steel valves are in a box in my attic. I have a running rebuilt l28et in the car, and a n42 sitting on a shelf. I will most likely put the cam in the stock engine and save the valves and n42 for later on when I get one of those PITA large exhaust AR's like your talking about. Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted July 16, 2013 Author Share Posted July 16, 2013 Update: I sent a cam to Delta Camshaft in Tacoma, WA. The price seemed fair and the guy sounded very knowledgeable when I spoke to him. He recommended the 272. He said it will only be .450" lift so I won't need to worry about new springs. I went to the track with the new tranny and I was really impressed with how the car launches now. I feel like my 60' are below 2 seconds. I just need the top-end that I hope the new cam will give me. This car has been a great learning experience. Thanks for everyone's suggestions. Quote Link to comment Share on other sites More sharing options...
Xnke Posted July 16, 2013 Share Posted July 16, 2013 Can you look on the box the cam came in and get the grind number? the "272" grind sounds awful familiar... Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted July 17, 2013 Author Share Posted July 17, 2013 He's regrinding my stock cam. I haven't gotten it back yet. The 272 is advertised duration. Quote Link to comment Share on other sites More sharing options...
Xnke Posted July 17, 2013 Share Posted July 17, 2013 Sounds like the 0.450" lift, 222* duration at 0.050" I picked up the other day. Did he tell you the lobe center? Quote Link to comment Share on other sites More sharing options...
skirkland1980 Posted July 17, 2013 Author Share Posted July 17, 2013 Yeah sounds about like the same grind. The lobe center will be maybe a degree or two wider than stock. What lash pad thickness are you using? I need to pick some up soon. Quote Link to comment Share on other sites More sharing options...
Xnke Posted July 18, 2013 Share Posted July 18, 2013 Lash pad thickness is VERY dependant on your valve job, cylinder head thickness, ect. You can estimate it by taking the base circle of the cam you have, minus the new base circle, divided by two, and add that number to the lash pad thickness you have now. That will get you in the ballpark...but it isn't necessarily the size you need. Quote Link to comment Share on other sites More sharing options...
Pyro Posted July 18, 2013 Share Posted July 18, 2013 Turbos typically like cams with more intake duration than exhaust. The theory is shorter exhaust duration makes a hotter and faster exhaust stream into the turbo. (pure exhaust) What turbo are you using? A stock turbo has a small turbine and makes lots of back pressure in the exhaust manifold. So stock turbos don't do well with any valve overlap. If you are using a more free flowing turbine then more overlap can be used. Quote Link to comment Share on other sites More sharing options...
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